Deann Smith, 23, whose accusations led to Sullinger’s arrest by Waltham police, had repeatedly asked for the criminal charges to be dismissed since the Aug. 31 incident between the couple in the home they shared in Waltham.

After the ruling by Waltham District Judge Gregory Flynn, Sullinger declined to discuss the case. Asked how he was doing, Sullinger said, “Ready to play.”

In paperwork filed by Sullinger’s attorney, Charles Rankin, the defense asked for the charges to be dropped, contending there was no evidence to support the allegations.

Rankin wrote that Smith, through her own attorney, has notified Middlesex District Attorney Marian T. Ryan’s office that she would not help prosecutors in a trial against Sullinger, 21.

Smith “will not appear and . . . if she were forced to appear, she would invoke her Fifth Amendment privilege against self-incrimination,” wrote Rankin, even though she was never accused of a crime. “Moreover, discovery in the case has revealed there are not excited utterances nor any other admissible evidence to support the charges.’’

In domestic violence cases, prosecutors can cite what a victim tells first responders — known legally as “excited utterances’’ — if victims refuse to testify against their alleged abusers.

A spokeswoman for Ryan said the decision by Smith not to cooperate with law enforcement stripped prosecutors of the key evidence they needed to pursue charges.

“Where the victim is a necessary witness to the case, without her testimony, we cannot sustain our burden of proof,’’ MaryBeth Long said. “So the judge dismissed the case. We were not in a position to go forward.’’

In a three-page affidavit, the attorney for Smith, Melinda Thompson, wrote that the couple argued on Aug. 31 in their Waltham apartment, and that Sullinger left for home in Ohio. Nine hours after the argument, according to the affidavit, Smith called Waltham police on their business line and reported the incident.

“Ms. Smith spoke with police and told them that she did not want to press charges against Mr. Sullinger,’’ the attorney said, describing the first contact between Smith and law enforcement. “She told them that she did not want to have him arrested. She also told police she did not want or need protection from Mr. Sullinger.’’

In the police report filed in court when the 6-foot-9-inch, 260-pound Sullinger was arrested in September, police said Smith told them that she confronted Sullinger, whom she suspected of cheating on her. The two argued verbally, and the argument intensified when Smith started packing up her belongings, according to the report.

“During this heated argument in the bedroom, Jared pushed her down onto the bed and got on top of her. Deann states she tried several times to get up, but he kept pinning her down and would not let her up,’’ Waltham police wrote in the report.

Smith and Sullinger began dating when both were students at Ohio State University and were living together at the time of the incident, according to records.

Smith has since moved back to Ohio, said Thompson, her attorney.

“They certainly still talk. They definitely speak, and they’re on good terms,’’ Thompson said. “At this point, they don’t have plans to move back in together. To be honest, I’m not sure about the status of the relationship.’’

Thompson would not offer an explanation as to why Smith called police nine hours after she argued with Sullinger.

“I don’t want to get into the question of why she called police, because of her privacy,’’ Thompson said. “I don’t want to discuss the specific allegations.’’

Thompson said Smith is not critical of Waltham police for pursuing charges against Sullinger, even though she told them she was never in fear of him.

“The police did their job,’' Thompson said.

Thompson also said that Smith wanted the case against Sullinger brought to an end.

“She wanted these charges dropped right away,” Thompson said. “I think it’s a good result for everyone. And I know Deann is happy to put this behind her.’’

Sullinger played just 45 games during his injury-shortened rookie season. But coming off back surgery, the forward is expected to be an impact player for the Celtics this season.

The Ohio State standout is the Celtics’ best rebounder, but he has said his conditioning is nowhere near where it needs to be.

Still, he was one of the Celtics’ most impressive players through training camp, and he averaged 10.1 points and 4.6 rebounds over 20.6 minutes in eight preseason games.